This invention is directed to a knob for installation on the end of a control shaft of a cam operated timer of the type used in household appliances and shown in U.S. Pat. No. 5,990,426. Such a knob permits rotation of the control shaft bi-directionally and movement of the shaft axially towards and away from the timer without dislodging the knob from the shaft. Due to the shape of the shaft passage entrance in the prior knob, it was necessary to manually rotate the knob to orient it relative to the shaft before assembly of the knob on the shaft of the timer.
The method of making the previous knob by injection molding required the use of a pair of molding tools such as core pins, one insertable from the shaft side and one insertable from the front side of the knob.
The knob of this invention is simpler to mold than the prior knob, reduces the amount of plastic necessary to mold the knob and facilitates the installation of the knob on to the shaft of the timer.
An object of this invention is a knob for a control shaft of a cam-operated timer than can be injection molded using a single collapsible stem hole core pin insertable from the shaft facing side of the knob.
Another object of this invention is a knob for a control shaft of a timer which knob can be assembled on the control shaft of the timer by rotation of the knob without requiring visual or tactile rotational alignment of the knob and the control shaft.
Still another object of this invention is a knob which resists accidental rotation relative to its shaft during its installation on the shaft.
Yet another object of this invention is a knob in which the quantity of plastic necessary to mold the knob is reduced relative to the prior knob without diminishing the strength of its core to a level it would not function.
An additional object of this invention is a knob for a control shaft of a cam-operated timer which can be formed with a blind shaft passage.
A further object of this invention is a knob having a blind passage which receives a control shaft with spring fingers which does not interfere with locking and unlocking movement of the spring fingers.
A still further object of this invention is a knob having a blind passage which receives a control shaft with spring fingers which securely holds the spring fingers in engagement with a shaft locking pin clear of the bottom wall of the blind passage.
Yet a further object of this invention is a knob having a blind passage for a control shaft with spring fingers secured by a locking pin equipped with a depressible cover to release the locking pin.
Other objects may be found in the following specification, claims and drawings.